RESUMEN
CONTEXT: One of the goals of endodontic therapy is the shaping and cleaning of the root canal system. In recent years, there has been multiple systems instrumentation, and changes in their dynamics are central to maintain the original shape of the canal after preparation. AIMS: The aim of this study was to evaluate centering and transportation in curved root canals after using ProTaper(®) and MTwo(®) in continuous rotation, Reciproc(®) in reciprocating motion, and a step-down manual instrumentation technique. SETTINGS AND DESIGN: Mesiobuccal roots of human extracted the first and second maxillary molars were selected and the canals (n = 60) were divided into four groups according to the preparation techniques: PT-ProTaper(®); MT-MTwo(®); RE-Reciproc(®); MI-manual instrumentation. SUBJECTS AND METHODS: The final apical diameter was standardized to a size 25. Centering and transportation were evaluated by cone-beam computed tomography and Adobe Photoshop 8.0 software. STATISTICAL ANALYSIS USED: The data were statistically analyzed by ANOVA and Tukey post hoc. RESULTS: Results of transportation showed no statistical differences (P > 0.05) between groups, and significantly, difference (P < 0.05) between ProTaper(®) and Reciproc(®) was found when evaluating centering ability in the apical third. CONCLUSIONS: We concluded that there were no differences in transportation between the evaluated systems for the preparation of curved root canals with an apical instrumentation diameter of #25. For centering ability, in the apical third, ProTaper(®) presented worst behavior when compared to Reciproc(®).
RESUMEN
Um dos objetivos da terapêutica endodôntica radical e a conformação e limpeza do sistema de canais radiculares. Nos últimos anos têm surgido múltiplos sistemas de instrumentação e variações em suas dinâmicas, sendo fundamental a manutenção da forma original do canal depois do preparo. O objetivo desse estudo foi avaliar a centralização e transporte de canais radiculares curvos, nos terços cervical e apical, utilizando os sistemas de rotação contínua ProTaper® e Mtwo®, de rotação alternada Reciproc® e uma técnica coroa-ápice de instrumentação manual. Foram selecionadas raízes mesio vestibulares de primeiros molares superiores humanos permanentes extraídos. Após a definição dos comprimentos, ângulos e raios de curvatura, os canais (n=60) foram divididos em quatro grupos experimentais, conforme os sistemas de preparo. O diâmetro apical final foi padronizado em #25. Tomografias computadorizadas antes e após o preparo foram feitas para mensuração do transporte e centralização dos canais e os resultados obtidos foram avaliados estatísticamente através de ANOVA e Tukey. Quando se utilizou diâmetro apical 25 nos preparos radiculares, não foram encontradas diferenças estatísticas no transporte dos canais entre os sistemas (p˃0.05). Na análise de centralização, diferença signficativa ocorreu na avaliação apical (p˂0.05) entre o sistema Reciproc e ProTaper, sendo que o sistema Reciproc apresentou o pior resultado.
One of the purposes of the radical endodontic therapy consists of cleaning and shaping of the root canal system. In recent years there have been multiple instrumentation systems and variations in their dynamics, being fundamental the fact of maintaining the original shape of the canal after mechanical preparation. The aim of this study was to evaluate the centering ability and transportation in curved root canals at the cervical and apical thirds, using systems with continuous motion, ProTaper ® and MTwo ®, reciprocating motion, Reciproc®, and a step-down manual instrumentation technique. Mesial buccal roots of human extracted first maxillary permanent molars were selected. After having determined the lengths, angles and radius of curvature, the canals (n = 60) were divided into four groups according with preparation systems. The final apical diameter was standardized in # 25. Computed tomographies were made to measure centering ability and transportation of the canals. The results were statistically analyzed by ANOVA and Tukey. When used apical preparation # 25, no statistical differences were found in the transportation between the systems (p ˃ 0,05). In the analysis of centering ratio, significantly difference occurred in the apical evaluation (p ˂ 0,05) between Reciproc and ProTaper systems, the Reciproc system showed the worst result.